Mo. Rev. Stat. § 272.030: Owners of stock liable for damages, when.

If any horses, cattle or other stock shall break over or through any lawful fence, as defined in section 272.020, and by so doing obtain access to, or do trespass upon, the premises of another, the owner of such animal shall be liable for any damages sustained if the owner of the trespassing horses, cattle, or other stock was negligent.